This Is Why We Get Stomach Grumbles When We're Hungry (And Full)

It's actually like an echo.

09/08/2016 7:43 AM AEST | Updated 09/08/2016 4:34 PM AEST
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Oh, stomach rumbles. The hollow (and sometimes high-pitched) gurgling, rumbling and growling that always seem to happen in quiet meetings, exams or on dates. Yay.

This loud noise our bowels sometimes makes is technically known as borborygmi, which is a pretty accurate word for how this phenomenon sounds.

Although stomach growling is commonly heard and associated with the feeling of hunger or an absence of food in the stomach, it can actually occur at any time, even on a full stomach, and we may not even hear it at all.

"I'm not 100 percent convinced that these stomach grumbles are perfectly related to prolonged sense of hunger," Zane Andrews -- an associate professor of physiology and neuroscientist who studies how food (and lack of food) affects the brain at Monash University -- told The Huffington Post Australia.

Instead, Andrews attributes these loud, intense monster growls to the process of food digesting and moving through not only our stomach, but also our intestine.


"When you eat, there's a normal process of the food going into the stomach, which get broken down and slowly enters the intestine, goes through the small and then the large, and all nutrients get absorbed," Andrews explained.

"Food entering the intestine can often be hours after you've actually consumed that food. The food needs to move down the intestine and so, often, somewhere between two and five hours after eating, you'll often feel these contractions in your intestine. That's essentially a normal process of moving that food along the intestine and the process of digestion."

On top of this, while this digestion and moving is happening, the food is breaking down and, in doing so, creates gas.

"Often what happens in the process of digestion is there are lots of microbes and bugs in your gut and they help to break down the food, ferment the food and this creates air that causes gas -- and gas can escape," Andrews said.

"Also, when food is moving through your gut there are pockets of gas that create noise and that can actually come up and resonate through the stomach. It resonates more loudly if the stomach is empty -- it's like an echo. The greater the pockets of air, the louder the grumble as the air escapes and moves."

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"I hope no one heard that."

This is one possible explanation for stomach grumbles. Andrews admits the other possible reason we experience stomach growling is when we're feeling hangry.

"I do accept the other explanation (and we've all felt it), but not many of us have fasted long enough to feel the full effect," he told HuffPost Australia.

"As food goes into the stomach it creates tension and when the stomach senses tension, there are nerve fibres that are innervating or touching the stomach, and they will send messages back to the brain and say, 'you've got food in your stomach, you should stop eating now'.

"So, the opposite can also occur. That is, if you've got an empty stomach there's no tension and some of these nerves that innervate the stomach can then feed back to the brain and say, 'hey, we really need to try and get food in here'."

Either way, stomach growls are perfectly normal and funny (albeit slightly embarrassing) phenomenon like hiccups which seem to always happen at the quietest, most important of times.

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